Arctic Cat Sno Pro 120 2011, Service Manual

Page: 370 / 535

7-2
Rear Suspension
SPECIAL TOOLS
A number of special tools must be available to the techni-
cian when servicing the rear suspension.

NOTE: Special tools are available from the Arctic
Cat Service Parts Department.
UNDERSTANDING THE SUSPENSION
Quick acceleration and the ability to go through the turns
with power are the most important handling qualities.
This section explains how the skid frame functions to
provide these two important handling qualities. Before
proceeding, however, note these terms.
Weight Transfer — A shift in the center of gravity in
any direction depends on the force applied.
Track Tension — The amount of tightness or looseness
of the track when correctly mounted in the chassis.
Spring Tension — The amount of force exerted on the
spring by either fork tension adjustment or eyebolt
adjustment.
Ski Pressure — The amount of force exerted downward
on the skis.
Good weight transfer characteristics are needed for fast
acceleration (shift of weight from skis to track) and for
cornering (shift of weight back to skis to hold the front
end in turns). Effective weight transfer depends on sus-
pension tension, position of rider, and the position of the
front arm limiter.
To understand how the suspension system works, think
of the entire system in terms of three points; the skid
frame rear axle center, the skid frame front arm, and the
ski saddle center.
Assume that the front arm functions as a stationary pivot
point between the rear axle center and the ski saddle cen-
ter. Also assume that the ski saddle center is the same
height off the ground as the rear axle center. This pro-
duces the standard position arrangement.
0728-180
Under acceleration when the center of gravity is trans-
ferred to the rear of the machine, the rear suspension col-
lapses slightly. This brings the rear arm point downward
and with the front arm stationary, the teeter-totter effect
reduces the pressure on the skis, position A.
However, for controlled cornering, more pressure is
needed on the skis. So when the driver decelerates com-
ing into a corner, the center of gravity is transferred for-
ward, putting the required pressure onto the skis and
reducing the pressure on the rear suspension, position C.
0728-181
This is essentially what weight transfer is all about — the
shift of weight to the rear of the machine for positive
traction and good acceleration or to the front of the
machine for positive handling and cornering control.
Suspension Setup Basics
FRONT ARM SPRING TENSION
Having very light front arm spring tension is desirable.
When riding in 4 in. or more of snow, the machine will be
quicker if the front spring tension is adjusted lightly.
If the spring tension is adjusted too stiff, the track angle
at the front of the skid frame is steep. This steep angle
prevents the snowmobile from getting up on plane and
slows down by 5 to 8 mph.
Description p/n
Shock Absorber Air Pump 2603-614
Floating Piston Installation/Location Tool Kit 0644-402
Idler Wheel Puller Kit 0644-122
Idler Wheel Puller Kit 0644-400
Floating Piston Removal Tool 0644-348
Inflation Needle 0744-020
Rear Suspension Spring Tool 0144-311
Gas Shock Rod/Body Clamping Tool 0644-425
Spanner Wrench - Fox Float Shock 0644-453
Handlebar Stand 5639-152
Manual
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